P0685
Système
Powertrain (Electrical)
Scanner requis
Full-system scanner (engine, ABS, SRS, transmission, service resets)

ECM/PCM Power Relay Control Circuit Open

Understand P0685, common causes, and the right FOXWELL scanner to diagnose it.

Main ECM power relay control circuit open — engine may not start or stall.

Symptômes courants

  • No-start
  • Stalling
  • Intermittent crank no-start

Causes typiques

  • Failed ECM relay
  • Open relay control wire
  • Blown fuse
  • ECM internal driver fault

Quel scanner choisir ?

Full-system scanner (engine, ABS, SRS, transmission, service resets)

Utilisez les données en direct et le freeze frame avant de remplacer des pièces. Les codes ABS, SRS et U nécessitent souvent un scanner mult systèmes.

Conseils de diagnostic

  • Enregistrez le freeze frame lors de la première apparition du code
  • Effacez le code uniquement après avoir corrigé la cause
  • Vérifiez les codes en attente associés
  • Vérifiez que la batterie est au-dessus de 12,4 V avant de suspecter un capteur

Scanners FOXWELL recommandés

Questions fréquentes

Can I diagnose P0685 with a basic code reader?
P0685 may set in the engine module, but related diagnostics often benefit from an enhanced or full-system scanner with live data and freeze frame.
Is it safe to drive with P0685?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.